An ALMA search for substructure and fragmentation in starless cores in Orion B North

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Hauptverfasser: Fielder, Samuel, Kirk, Helen, Dunham, Michael, Offner, Stella
Format: Preprint
Veröffentlicht: 2024
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author Fielder, Samuel
Kirk, Helen
Dunham, Michael
Offner, Stella
author_facet Fielder, Samuel
Kirk, Helen
Dunham, Michael
Offner, Stella
contents We present Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 3 observations of 73 starless and protostellar cores in the Orion B North molecular cloud. We detect a total of 34 continuum sources at 106 GHz, and after comparisons with other data, 4 of these sources appear to be starless. Three of the four sources are located near groupings of protostellar sources, while one source is an isolated detection. We use synthetic observations of a simulation modeling a collapsing turbulent, magnetized core to compute the expected number of starless cores that should be detectable with our ALMA observations and find at least two (1.52) starless core should be detectable, consistent with our data. We run a simple virial analysis of the cores to put the Orion B North observations into context with similar previous ALMA surveys of cores in Chamaeleon I and Ophiuchus. We conclude that the Chamaeleon I starless core population is characteristically less bounded than the other two populations, along with external pressure contributions dominating the binding energy of the cores. These differences may explain why the Chamaeleon I cores do not follow turbulent model predictions, while the Ophiuchus and Orion B North cores are consistent with the model.
format Preprint
id arxiv_https___arxiv_org_abs_2404_13520
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle An ALMA search for substructure and fragmentation in starless cores in Orion B North
Fielder, Samuel
Kirk, Helen
Dunham, Michael
Offner, Stella
Astrophysics of Galaxies
We present Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 3 observations of 73 starless and protostellar cores in the Orion B North molecular cloud. We detect a total of 34 continuum sources at 106 GHz, and after comparisons with other data, 4 of these sources appear to be starless. Three of the four sources are located near groupings of protostellar sources, while one source is an isolated detection. We use synthetic observations of a simulation modeling a collapsing turbulent, magnetized core to compute the expected number of starless cores that should be detectable with our ALMA observations and find at least two (1.52) starless core should be detectable, consistent with our data. We run a simple virial analysis of the cores to put the Orion B North observations into context with similar previous ALMA surveys of cores in Chamaeleon I and Ophiuchus. We conclude that the Chamaeleon I starless core population is characteristically less bounded than the other two populations, along with external pressure contributions dominating the binding energy of the cores. These differences may explain why the Chamaeleon I cores do not follow turbulent model predictions, while the Ophiuchus and Orion B North cores are consistent with the model.
title An ALMA search for substructure and fragmentation in starless cores in Orion B North
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2404.13520